1. Field of the Invention
The present invention relates to recording and reproducing method and apparatus, processing apparatus, and recording medium for a video signal having copy control information including another information, that is, electronic watermark information and a copy generation management signal multiplexed or embedded on/in image data, especially, a video signal in order to control reproduction or recording of an original image or to clarify the source of the image.
2. Description of the Prior Art
Among the several methods for embedding electronic watermark (data hidden or embedded) information in a video signal, representative one is described in xe2x80x9cData Hiding Techniquexe2x80x9d in ITE Technical Report, Vol. 21, No. 31, pp. 3-8. Another conventional information embedding technique is described in Nikkei Electronics, No. 683, pp. 99-107, 1997. It is described that, in these conventional techniques, information different from that of an inherent video signal is embedded in a part of the video signal by using statistical characteristics of an image and a control signal showing the source of the inherent image and further determining whether the signal can be reproduced or not by using the embedded information upon reproduction is generated. In the conventional technique, information different from that of an inherent image is embedded in a part of the image by using statistical characteristics of the image and a control signal showing the source of the inherent image and further determining whether the signal can be reproduced or not by using the embedded information upon reproduction is generated.
Generally widely recognized copy control is carried out by xe2x80x9cfull copy inhibitionxe2x80x9d or xe2x80x9ccopy only once permissionxe2x80x9d. The latter is positioned as a copy generation management system (CGMS). In case of permitting copy only once, the signal is rewritten upon copy operation from xe2x80x9ccopy once permissionxe2x80x9d to xe2x80x9ccopy inhibitionxe2x80x9d.
The foregoing literatures, however, do not describe that copy control is performed by a combination of such a technique and electronic watermark information.
It is an object of the invention to provide recording and reproducing method and apparatus, processing apparatus, and recording medium for a video signal having copy control information, which can easily discriminate whether the signal is reproducible or not.
Another object of the invention is to provide recording and reproducing method and apparatus, processing apparatus, and recording medium for a video signal having copy control information such as electronic watermark information, copy generation management signal, and the like.
Further another object of the invention is to provide reproducing method and apparatus and processing apparatus for a video signal having copy control information, which can inhibit outputting of a reproduced signal when the copy control information is illegally operated.
Further another object of the invention is to provide reproducing method and apparatus and processing apparatus for a video signal which can perform copy control in consideration of copy generation management system by using copy control information included in a luminance signal of a video signal which is once recorded to VCR, video disk, or the like.
In a recording medium of the invention, a video signal, electronic watermark information which is embedded in the video signal and has copy control information, and a CGMS signal for copy control inserted into the video signal are recorded. The electronic watermark information can be obtained by changing a luminance value of a luminance signal in a predetermined position of a video signal. Preferably, a range of changing the luminance value of the luminance signal is set to a permissible alteration range. The CGMS signal is inserted into a region outside of a scan region of the video signal. Preferably, the CGMS signal is inserted into a region out of the scan region near a horizontal sync signal. Preferably, the CGMS signal is a signal of two or larger bits. The electronic watermark information has information of either copy free, copy-once-permission, or copy inhibition. The CGMS signal has information of either copy free, copy-once-permission, or copy inhibition.
A recording method according to the invention comprises: a step of forming electronic watermark information by embedding copy control information into the luminance signal by changing a luminance value in a predetermined position of the luminance signal; and a step of inserting a CGMS signal having copy control information into a region out of a scan region of the video signal.
A recording method according to the invention comprises: a step of calculating a visually durable range even when a luminance value of a luminance signal included in a video signal is changed; a step of generating electronic watermark information having copy control information by changing the luminance value of a luminance signal in a predetermined position within the calculated range; and a step of generating a CGMS signal which has copy control information and is inserted into a region out of a scan region of the video signal.
A recording method according to the invention comprises: a step of calculating a visually durable range even when a luminance value of a luminance signal included in a video signal is changed; a step of generating electronic watermark information having copy control information by changing the luminance value when the luminance value to be changed of the luminance signal in a predetermined position lies within the calculated range; and a step of generating a CGMS signal which has copy control information and is inserted into a region out of a scan region of the video signal.
A reproducing method according to the invention for reproducing electronic watermark information and a CGMS signal from a video signal including the electronic watermark information in which copy control information is embedded by changing a luminance value of a luminance signal and the CGMS signal having copy control information inserted into a region out of a scan region of the video signal from a recording medium and for controlling outputting of the video signal, the method comprises: a step of detecting the electronic watermark information; a step of detecting the CGMS signal; and a step of stopping the outputting of the video signal when the copy control information obtained from the electronic watermark information and the copy control information obtained from the CGMS signal lacks in rationality. Each of the electronic watermark signal and the CGMS signal has either copy inhibition information or copy-once permission information. Further, the method comprises a step of outputting and displaying the video signal by the copy-once permission information obtained from the electronic watermark information and the copy inhibition information obtained from the CGMS signal. The method further comprises a step of outputting and displaying the video signal by copy inhibition information obtained from the electronic watermark information and copy inhibition information obtained from the CGMS signal. The method further comprises a step of stopping the outputting of the video signal when the CGMS signal is not reproduced.
A reproducing method of the invention comprises: a step of discriminating the kind of a disk; and a step of stopping outputting of the video signal when the copy control information obtained from the electronic watermark information, the copy control information obtained from the CGMS signal, and the disk kind information lacks in rationality. The method further comprises a step of outputting the video signal when the disk is read only disk, the electronic watermark information is a copy-once-permitted signal, and the CGMS signal is a recording-once-permitted signal. The method further comprises a step of stopping the outputting of the video signal when the disk is a recordable disk, the electronic watermark information is a copy-once-permitted signal, and the CGMS signal is a recording-once-permitted signal.
A reproduction method of the invention for reproducing electronic watermark information and a CGMS signal from a video signal including the electronic watermark information in which either copy inhibition or copy-once-permission is embedded by changing a luminance value of a luminance signal and the CGMS signal having information of either copy inhibition or copy-once-permission from a recording medium in order to control recording of the video signal, comprises: a step of detecting copy control information embedded in the electronic watermark information; a step of detecting the copy control information from the CGMS signal; a step of discriminating whether the copy information embedded in the electronic watermark information and that in the CGMS signal has a rational relation or not; and a step of permitting recording of the video signal only when the relation is rational. The step of discriminating the rational relation discriminates the relation as rational from a state where the copy-once-permission information obtained from the electronic watermark information and the copy-once-permission information obtained from the CGMS signal is rewritten to copy inhibition information. It is discriminated as rational from a state where the copy-once-permission information obtained from the electronic watermark information is rewritten to copy inhibition and copy-once-permission information obtained from the CGMS signal is rewritten to copy inhibition information.
A recording apparatus according to the invention comprises: a permissible alteration range calculating circuit for calculating an alternation range of a luminance value of a luminance signal included in a video signal in accordance with the luminance value; an information embedment processing circuit for embedding electronic watermark information having copy control information by changing the luminance value of the luminance signal in a predetermined position within the calculated permissible alternation range; a generating circuit for generating a CGMS signal having copy control information; and an adding circuit for adding the CGMS signal to a region out of a scan region range of the luminance signal in which the electronic watermark information is embedded.
A recording apparatus according to the invention comprises: a permissible alteration range calculating circuit for calculating an alternation range of a luminance value of a luminance signal included in a video signal in accordance with the luminance value; an information embedment processing circuit for embedding electronic watermark information having copy control information by changing the luminance value of the luminance signal when the luminance value of the luminance signal in a predetermined position is within the calculated permissible alternation range; a generating circuit for generating a CGMS signal having copy control information; and an adding circuit for adding the CGMS signal to a region out of a scan region range of the luminance signal in which the electronic watermark information is embedded.
An apparatus for processing a video signal having copy control information according to the invention for reproducing electronic watermark information and a CGMS signal from a video signal including the electronic watermark information in which copy control information is embedded by changing a luminance value of a luminance signal and the CGMS signal having copy control information inserted into a region out of a scan region of the video signal from a recording medium in order to control outputting of the video signal, comprises: a circuit for processing the video signal reproduced from the recording medium; an electronic watermark detecting circuit; a CGMS signal detecting circuit for detecting the CGMS signal; and an output control circuit for controlling the video signal processing circuit from the detected electronic watermark information and the detected CGMS signal. The output control circuit controls the video signal processing circuit so as to output a video signal by copy-once-permission information obtained from the electronic watermark information and copy inhibition information obtained from the CGMS signal. The output control circuit controls the video signal processing circuit so as to output the video signal by copy inhibition information obtained from the electronic watermark information and copy inhibition information obtained from the CGMS signal. The output control circuit controls the video signal processing circuit so as not to output the video signal when the CGMS signal is not detected. When the recording medium is a recordable medium, the output control circuit controls the video signal processing circuit so as not to output the video signal by copy-once-permission information obtained from the electronic watermark information and copy-once-permission information obtained from the CGMS signal. When the recording medium is a read only medium, the output control circuit controls the video signal processing circuit so as to output the video signal by copy-once-permission information obtained from the electronic watermark information and copy-once-permission information obtained from the CGMS signal. The processing apparatus has a circuit for discriminating the kind of a disk. When an output of the disk kind discriminating circuit is a signal indicative of a recordable disk, the output control circuit controls the video signal processing circuit so as not to output the video signal by copy-once-permission information obtained from the electronic watermark information and copy-once-permission information obtained from the CGMS signal. When an output of the disk kind discriminating circuit is a signal indicative of a read only disk, the output control circuit controls the video signal processing circuit so as to output the video signal by copy-once-permission information obtained from the electronic watermark information and copy-once-permission information obtained from the CGMS signal.
A processing apparatus according to the invention comprises a circuit for updating the generation of the CGMS signal; and a rewriting and controlling circuit which controls outputting of a video signal and controls whether the video signal can be outputted or not by the electronic watermark signal and the CGMS signal. The rewriting and controlling circuit outputs the video signal from the rewriting and controlling circuit by copy-once-permission information derived from the electronic watermark information and copy-once-permission information derived from the CGMS signal, and rewrites copy-once-permission information of the CGMS signal to copy inhibition information. Or the rewriting and controlling circuit outputs the video signal from the rewriting and controlling circuit by copy-once-permission information derived from the electronic watermark information and copy-once-permission information derived from the CGMS signal, and rewrites copy-once-permission information obtained from the electronic watermark information to copy inhibition and copy-once-permission information derived from the CGMS signal to copy inhibition information.
A recording and reproducing apparatus according to the invention compares: a recording device for recording a video signal having copy control information including a bit for copy control and electronic watermark information in which a control signal generated by the bit is embedded, and a reproducing device including a detector for detecting the bit when the video signal is reproduced and a signal derived from electronic water mark for comparing the bit and the signal o obtained from electronic water mark for outputting video signal when they have a predetermined relation. only when the electronic watermark information is detected and the signal by the directly detected bit indicates one generation copy permission, the signal generated by the bit generating means is changed, the changed signal, inputted electronic watermark recording signal and video signal are simultaneously recorded, and the recording operation after that is inhibited. The bit is rewritten to a signal indicative of inhibition only when the bit shows copy one generation permission and is recorded simultaneously with the electronic watermark recording signal and video signal.
A reproducing apparatus according to the invention for reproducing a video signal from a disk on which a video signal in which electronic watermark information is recorded and a bit for copy control is written, comprises: electronic watermark information detecting means; means for detecting a signal recorded by a bit generating means; disk discriminating means for discriminating the disk; and means for reproducing the video signal written in the disk when the disk is discriminated as a read only disk by the disk discriminating means and the electronic watermark information and the bit information coincide with each other. When it is discriminated by the disk discriminating means that the disk is recordable and reproducible and the electronic watermark information coincides with bit information and when one generation copy permission of a signal generated by bit information generating means is correctly changed, the video signal is reproduced. In the case where the disk is recordable and reproducible, the video signal is reproduced only when the electronic watermark information is one generation copy permission information and information of the bit generating means is copy inhibition information.
These and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.